Oscillatory linear actuator and cutting device

ABSTRACT

An oscillatory linear actuator includes: an output movable element which is reciprocated by a periodically varying magnetic field and performs work on an object; and a vibration absorbing movable element which is reciprocated at a phase opposite to a phase of the output movable element and reduces vibration of the oscillatory linear actuator. The vibration absorbing movable element is lighter in weight than the output movable element.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of Japanese PatentApplication Number 2017-082980 filed on Apr. 19, 2017, the entirecontent of which is hereby incorporated by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to an oscillatory linear actuator whichis reciprocated along an axis and a cutting device which includes theoscillatory linear actuator and cuts an object such as body hair andgrass.

2. Description of the Related Art

In an oscillatory linear actuator which is reciprocated along an axis,in particular, a device held by a human hand, two types of movableelements which have approximately the same weight and which are drivenat mutually opposite phases may be disposed parallel to each other inorder to reduce vibration to be transmitted to the hand. Moreover,Japanese Unexamined Patent Application Publication No. 2005-185067discloses a configuration in which those two types of movable elementsare connected to each other, and a movable blade for cutting an object,such as body hair, is attached to only one of the movable elements.

SUMMARY

However, in the oscillatory linear actuator as described above, althoughonly one of the movable elements performs work on the object, themovable elements both with the same weight are oscillated at oppositephases in order to reduce vibration. This results in wasteful energyconsumption.

The present disclosure has been conceived to solve such a conventionalproblem. An object of the present disclosure is to provide anoscillatory linear actuator which is capable of achieving powerful driveby concentrating the thrust force of the oscillatory linear actuator onthe output movable element which performs work on the object, at thesame time as reducing vibration, and a cutting device which includes theoscillatory linear actuator.

In order to achieve the object, an oscillatory linear actuator accordingto one aspect of the present disclosure includes: an output movableelement which is reciprocated by a periodically varying magnetic fieldand performs work on an object; and a vibration absorbing movableelement which is reciprocated at a phase opposite to a phase of theoutput movable element and reduces vibration of the oscillatory linearactuator. The vibration absorbing movable element is lighter in weightthan the output movable element.

With this, the thrust force of the oscillatory linear actuator is notgreatly reduced due to driving of the vibration absorbing movableelement which does not perform work on the object. Hence, energy can beefficiently used.

As a result, the oscillatory linear actuator is capable of efficientlyusing energy, and also capable of improving the thrust force, leading topowerful driving of the oscillatory linear actuator.

Moreover, it may be that the vibration absorbing movable elementincludes a weight for weight adjustment.

With this, weight adjustment of the output movable element and thevibration absorbing movable element can be easily performed.

Moreover, it may be that the output movable element includes a permanentmagnet, and the vibration absorbing movable element includes a permanentmagnet, and the permanent magnets of the output movable element and thevibration absorbing movable element are reciprocated by a single fixedelectromagnet.

Moreover, a cutting device according to another aspect of the presentdisclosure includes: the oscillatory linear actuator; a movable bladeincluded in the output movable element; and a stationary blade whichrubs against the movable blade.

According to the present disclosure, the thrust force of the oscillatoryliner actuator is not used greatly for the vibration absorbing movablebody, thereby improving the thrust force to be output.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure.

FIG. 1 is a perspective view of an appearance of a cutting device whichincludes an oscillatory linear actuator according to an embodiment andremoves body hair;

FIG. 2 is a perspective view of a schematic configuration of theoscillatory linear actuator according to the embodiment;

FIG. 3 is a front view of a schematic configuration of the oscillatorylinear actuator according to the embodiment;

FIG. 4 is a side view of a schematic configuration of the oscillatorylinear actuator according to the embodiment;

FIG. 5 is a rear view of a schematic configuration of the oscillatorylinear actuator according to the embodiment;

FIG. 6 is an exploded perspective view of a schematic configuration ofthe oscillatory linear actuator according to the embodiment; and

FIG. 7 is a perspective view of a schematic configuration of each of anoutput movable element and a vibration absorbing movable elementaccording to the embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT

Next, an embodiment of an oscillatory linear actuator and a cuttingdevice including the oscillatory linear actuator according to thepresent disclosure will be described with reference to the drawings.Note that the following embodiment merely illustrates an example of theoscillatory linear actuator and the cutting device including theoscillatory linear actuator according to the present disclosure. Assuch, the scope of the present disclosure is demarcated by the scope ofthe language in the claims using the below embodiment as a reference,and is not intended to be limited merely by the following embodiment.Therefore, among the structural elements in the following embodiment,structural elements not recited in any one of the independent claimsdefining the most generic part of the inventive concept are described aspreferred structural elements, and are not absolutely necessary toachieve the object according to the present disclosure.

Note that the drawings are schematic illustrations in which emphasis,omission, and adjustment in proportion are made as appropriate toillustrate the present disclosure, and may differ from the actual shape,positional relationship, and proportion.

[Cutting Device]

FIG. 1 is a perspective view of an appearance of a cutting device whichincludes an oscillatory linear actuator according to the embodiment andremoves body hair.

As illustrated in FIG. 1, cutting device 1 is, for example, an electrichair clipper, and includes case 2, blade unit 3, and switch 4. Case 2houses oscillatory linear actuator 100 (see, for example, FIG. 2) fordriving blade unit 3.

Blade unit 3 is attached to the top part of case 2. Blade unit 3 has afunction of cutting body hair such as head hair. Specifically, bladeunit 3 includes stationary blade 31 and movable blade 32. Stationaryblade 31 is fixed to the top part of case 2. Movable blade 32 isconnected to shaft 520 (see, for example, FIG. 2) of output movableelement 101 of oscillatory linear actuator 100, and is part of outputmovable element 101 to be described later. Moreover, stationary blade 31and movable blade 32 are in contact with each other at their opposingfaces. Movable blade 32 is reciprocated relative to stationary blade 31by oscillatory linear actuator 100. This reciprocation causes blade unit3 to cut hair.

[Oscillatory Linear Actuator]

Next, oscillatory linear actuator 100 will be described in details.

FIG. 2 is a perspective view of a schematic configuration of theoscillatory linear actuator according to the embodiment.

FIG. 3 is a front view of a schematic configuration of the oscillatorylinear actuator according to the embodiment.

FIG. 4 is a side view of a schematic configuration of the oscillatorylinear actuator according to the embodiment.

FIG. 5 is a rear view of a schematic configuration of the oscillatorylinear actuator according to the embodiment.

FIG. 6 is an exploded perspective view of a schematic configuration ofthe oscillatory linear actuator according to the embodiment.

FIG. 7 is a perspective view of a schematic configuration of each of theoutput movable element and the vibration absorbing movable elementaccording to the embodiment.

Note that, in the drawings, respective structural elements areillustrated in a three-dimensional orthogonal coordinate system wherethe x-axis direction indicates the direction in which the output movableelement and the vibration absorbing movable element oscillate, they-axis direction indicates the direction in which movable blade 32 andstationary blade 31 are arranged, and the z-axis direction indicates thedirection in which the shaft of the output movable element extends. Notethat the z-axis direction does not necessarily indicate the verticaldirection depending on the state of use. However, for illustrativepurposes, descriptions may be given below assuming that the x-y plane isthe horizontal plane, and the z-axis direction indicates the verticaldirection.

As illustrated in the drawings (in particular, FIG. 6 and FIG. 7),oscillatory linear actuator 100 includes output movable element 101,vibration absorbing movable element 102, electromagnetic core block 200,and frame 400.

[Output Movable Element]

Output movable element 101 is reciprocated by a periodically varyingmagnetic field, and performs work on an object such as body hair. In thepresent embodiment, output movable element 101 includes movable blade32, body 510, first magnet 301, first yoke 303, and first weight 305.

Body 510 is a structural component which forms the framework of outputmovable element 101. Body 510 is attached to frame 400. Body 510 iscranked in an overall view. Body 510 includes: attachment part 512 whichis disposed on the x-y plane; shaft 520 which is disposed on one end ofattachment part 512 along the y-axis and which extends to movable blade32 along the z-axis; and weight support 530 which extends in theopposite direction to shaft 520 from the other end of attachment part512 along the z-axis, and which holds first weight 305.

The tip of shaft 520 has an approximately cylinder (elliptic cylinder)shape to which movable blade 32 is attached.

Weight support 530 holds first weight 305 at a position apart fromattachment part 512 in order to keep movable blade 32 balanced againstattachment part 512.

First magnet 301 is a permanent magnet which is attached belowattachment part 512. First magnet 301 has a north pole at one end and asouth pole at the other end along the x-axis. First magnet 301 isreciprocated along the x-axis by the work of the periodically varyingmagnetic field generated from electromagnetic core block 200, andgenerates a thrust force which reciprocates movable blade 32.

First yoke 303 is made of a magnetic material which concentrates themagnetic flux of first magnet 301 and increases the work with themagnetic field generated from electromagnetic core block 200.

First weight 305 is disposed opposite to movable blade 32 relative tofirst magnet 301, and adjusts the position of the center of mass ofoutput movable element 101.

[Vibration Absorbing Movable Element]

Vibration absorbing movable element 102 is reciprocated at a phaseopposite to the phase of output movable element 101, and reduces theoverall vibration of oscillatory linear actuator 100. In the presentembodiment, vibration absorbing movable element 102 includes connector309, second magnet 302, second yoke 304, and second weight 306.

Connector 309 is a structural component which forms the framework ofvibration absorbing movable element 102, and is attached to frame 400.

Second magnet 302 is a permanent magnet which is attached belowconnector 309. Second magnet 302 has a south pole at one end and a northpole at the other end along the x-axis. The polarities of second magnet302 are disposed so as to be opposite to the polarities of first magnet301. For example, along the x-axis, when the negative end of firstmagnet 301 is a north pole, and the positive end of first magnet 301 isa south pole, the negative end of second magnet 302 is a south pole andthe positive end of second magnet 302 is a north pole. In a similarmanner to first magnet 301, second magnet 302 is reciprocated along thex-axis at a phase opposite to the phase of first magnet 301 by the workof the periodically varying magnetic field which is generated fromelectromagnetic core block 200.

Second yoke 304 is made of a magnetic material which concentrates themagnetic flux of second magnet 302 and increases the work with themagnetic field generated from electromagnetic core block 200.

Second weight 306 adjusts the weight balance against output movableelement 101.

Here, vibration absorbing movable element 102 is lighter in weight thanoutput movable element 101. In other words, in the present embodiment,the total weight of connector 309, second magnet 302, second yoke 304,second weight 306, and components which reciprocate integrally such asfastening components (except for a portion of frame 400) is less thanthe total weight of body 510, first magnet 301, first yoke 303, firstweight 305, movable blade 32, and components which reciprocateintegrally such as fastening components (except for a portion of frame400).

[Electromagnetic Core Block]

Electromagnetic core block 200 is a device which generates a drive forcewhich reciprocates output movable element 101 in the oscillationdirection (the x-axis direction in the drawings), and includes coilbobbin 220, coil 230, core 240, and base 250. In the present embodiment,electromagnetic core block 200 also reciprocates vibration absorbingmovable element 102.

Coil 230 is a component around which electrically conductive wire isspirally wound, and is capable of generating a magnetic field when anelectric current is applied to the wire. The polarities of the magneticfield generated by an application of an alternating current to coil 230can be periodically and repeatedly reversed, which allows output movableelement 101 and vibration absorbing movable element 102 to reciprocate.

Coil bobbin 220 is a component which severs as a base for forming a coilby winding electrically conductive wire around coil bobbin 220. In thepresent embodiment, coil bobbin 220 is made of an insulating materialand has a square tube shape.

Core 240 is made of a magnetic material, and guides the magnetic fieldgenerated within coil 230 to a predetermined position. In the presentembodiment, core 240 is a component having an E-shape in a side view,and integrally includes a pillar which pierces coil bobbin 220, twopillars disposed on the both sides of coil bobbin 220, and a base partwhich connects these pillars at the lower end of core 240. Note that theshape of core 240 is not limited to the E-shape, but may be any othershapes such as a U-shape.

Base 250 is, for example, made of an insulating material, and supportscore 240 and coil bobbin 220 via core 240. Base 250 holds core 240, coilbobbin 220, and coil 230 at predetermined positions relative to frame400.

[Frame]

Frame 400 holds output movable element 101 and vibration absorbingmovable element 102 while permitting reciprocation of output movableelement 101 and vibration absorbing movable element 102. Moreover, frame400 maintains spaces between output movable element 101, vibrationabsorbing movable element 102, and electromagnetic core block 200. Inthe present embodiment, frame 400 is integrally made of resin, forexample, and includes first holder 410 which holds output movableelement 101, second holder 420 which holds vibration absorbing movableelement 102, a pair of connection springs 431 and 432 which connectfirst holder 410 and second holder 420, and third holder 440 which holdselectromagnetic core block 200.

First holder 410 includes first fixing part 411 elongated along thex-axis, and a pair of first springs 412 suspended from the both ends offirst fixing part 411 and connected to third holder 440.

Output movable element 101 is attached to first fixing part 411. In thepresent embodiment, first magnet 301 and first yoke 303 are attached tofirst fixing part 411 from below in the aforementioned order, andattachment part 512 is attached to first fixing part 411 from above.Moreover, these are fastened by fastening components (for example,screws).

Second holder 420 is arranged side by side with first fixing part 411,and includes long plate-shaped second fixing part 421 which extendsalong the x-axis, and a pair of second springs 422 suspended from theboth ends of second fixing part 421 and connected to third holder 440.Second holder 420 is adjacent to first holder 410 along the y-axis.

Vibration absorbing movable element 102 is attached to second fixingpart 421. In the present embodiment, second magnet 302 and second yoke304 are attached to second fixing part 421 from below in theaforementioned order, and connector 309 and second weight 306 areattached to second fixing part 421 from above in the aforementionedorder.

A pair of connection springs 431 are flat plate springs which are curvedand connects first holder 410 and second holder 420 so as to be freelyoscillate. Specifically, among the pair of connection springs 431, oneof connection springs 431 connects one end of first fixing part 411 offirst holder 410 and one end of second fixing part 421 of second holder420. Moreover, the other one of connection springs 431 connects theother end of first fixing part 411 of first holder 410 and the other endof second fixing part 421 of second holder 420.

Moreover, connection springs 431 have such a structure that, along thex-axis, the amplitude of vibration absorbing movable element 102 ispermitted to be greater than the amplitude of output movable element101, that is, the amplitude of second fixing part 421 is permitted to begreater than the amplitude of first fixing part 411.

Third holder 440 is a frame having opening 441 which is rectangular in atop view. Third holder 440 holds electromagnetic core block 200 withelectromagnetic core block 200 being inserted to opening 441 of thirdholder 440.

Moreover, first spring 412 of first holder 410 and second spring 422 ofsecond holder 420 are connected to third holder 440. Accordingly, firstspring 412 and second spring 422 oscillate with the connected portionsof third holder 440 being a point of origin.

[Operation]

Next, the operations performed by oscillatory linear actuator 100 willbe described.

When an alternating current is supplied to coil 230 of electromagneticcore block 200 which forms an electromagnet, the state of the northpole, the south pole, and the north pole (in this arrangement order) andthe state of the south pole, the north pole, and the south pole (in thisarrangement order) are periodically switched on the top end surfaces ofrespective pillars of core 240.

In contrast, first magnet 301 held by first holder 410 and second magnet302 held by second holder 420 are disposed so that the polarities of therespective magnets are reversed. Accordingly, the magnetic forcegenerated from single coil 230 generates opposing forces along thex-axis on first magnet 301 and second magnet 302, which causes firstmagnet 301 and second magnet 302 to linearly move in the oppositedirections. As a result, output movable element 101 and vibrationabsorbing movable element 102 oscillate at the opposite phases.

Advantageous Effects, Etc.

As described above, in oscillatory linear actuator 100 included incutting device 1 according to the present embodiment, vibrationabsorbing movable element 102 is set to be lighter in weight than outputmovable element 101. Accordingly, the thrust force generated byoscillatory linear actuator 100 is not reduced by vibration absorbingmovable element 102 which does not contribute to cutting of an objectsuch as body hair. This allows the thrust force to be used efficientlyfor cutting the object. Therefore, the thrust force of oscillatorylinear actuator 100 can be efficiently assigned to output movableelement 101, which allows the object to be cut with power.

Note that the present disclosure is not limited to the above embodiment.For example, other embodiments that can be realized by arbitrarilycombining the structural elements described in the present specificationor by removing some structural elements may be embodiments of thepresent disclosure. Moreover, modifications obtainable through variouschanges to the above-described embodiment that can be conceived by aperson of ordinary skill in the art without departing from the essenceof the present disclosure, that is, the meaning of the recitations inthe claims are included in the present disclosure.

For example, the shape and the structure of output movable element 101are not limited to the above embodiment. For example, in the case whereelectromagnetic core block 200 includes a permanent magnet, anelectromagnet may be provided in output movable element 101.

Moreover, output movable element 101 may include a plurality of workparts such as a plurality of movable blades 32. Moreover, even if outputmovable element 101 is divided into a plurality of elements, if thoseelements oscillate together at the same phase and generate a thrustforce acting on an object, they are considered to be output movableelement 101. Moreover, it may be that the weight distribution of dividedoutput movable elements 101 does not need to be equal. It is acceptableif the overall weight of output movable elements 101 is greater than theoverall weight of vibration absorbing movable element 102.

Moreover, in a similar manner to output movable element 101, the shapeand the structure of vibration absorbing movable element 102 are notlimited to the above embodiment. Vibration absorbing movable element 102may include an electromagnet.

Moreover, output movable element 101 may include a plurality of workparts such as a plurality of movable blades 32. Moreover, even if outputmovable element 101 is divided into a plurality of elements, if thoseelements oscillate together at the same phase and generate a thrustforce acting on an object, they are considered to be output movableelement 101. Moreover, vibration absorbing movable element 102 may bedivided into a plurality of elements as long as the divided elementsoscillate at the phase opposite to the phase of output movable element101.

Moreover, it has been described that vibration absorbing movable element102 oscillates due to interaction with electromagnet core block 200.However, it may be that vibration absorbing movable element 102 does notwork with the magnetic force generated from electromagnetic core block200, but functions as a dynamic vibration absorber connected to outputmovable element 101 with an elastic member. In this case, vibrationabsorbing movable element 102 does not need to include a permanentmagnet and an electromagnet.

Although only some exemplary embodiments of the present disclosure havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the present disclosure. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to a cutting device which removesbody hair such as an electric clipper and an electric razor, and acutting device which cuts grass and tree branches.

What is claimed is:
 1. An oscillatory linear actuator comprising: anoutput movable element which is reciprocated by a periodically varyingmagnetic field and performs work on an object; and a vibration absorbingmovable element which is reciprocated at a phase opposite to a phase ofthe output movable element and reduces vibration of the oscillatorylinear actuator, wherein the vibration absorbing movable element islighter in weight than the output movable element.
 2. The oscillatorylinear actuator according to claim 1, wherein the vibration absorbingmovable element includes a weight for weight adjustment.
 3. Theoscillatory linear actuator according to claim 1, wherein the outputmovable element includes a permanent magnet, and the vibration absorbingmovable element includes a permanent magnet, and the permanent magnetsof the output movable element and the vibration absorbing movableelement are reciprocated by a single fixed electromagnet.
 4. A cuttingdevice comprising: the oscillatory linear actuator according to claim 1;a movable blade included in the output movable element; and a stationaryblade which rubs against the movable blade.